The present invention relates to water and fire resistant materials and methods of making the same. The present invention also relates to compositions used to impart water and fire resistance to a wide range of cellulosic materials including wood-based fibers and particles, cellulose wafers, wood strands, and organic waste products.
Natural wood, wood particles, fibers, and chips have many desirable properties and for this reason are widely used in wood composite construction materials. However, certain disadvantages or drawbacks exist with these construction materials. In particular, the wood-based products have not only an inherent combustibility but also a tendency to swell when exposed to moisture. This swelling causes a loss in cohesive and structural strength which in turn restricts the scope of use of such construction materials.
In addition, due to the significant reduction in the available supply of veneer grade lumber used in the manufacture of plywood, there has been a dramatic rise in the cost of such veneer. This has led to the economic necessity of using "waste" sub-products such as soft wood and hard wood particles, chips, wafers, and fibers to produce construction materials (e.g., panels, flooring, wallboards, replacement lumber, ceiling panels, roof sheathing, and doors).
Improvements in manufacturing processes have led to some increase in the strength and dimensional stability of products manufactured from wood waste fiber and organic by-product materials which are currently used to make a wide range of construction and industrial products. Such products include, for example, oriented strand board (OSB), medium density fiber board (MDF), particle board, fiber mat, pressboard, gypsum fiber board, fiber board and cement fiber board.
Although large amounts of construction and industrial products are manufactured worldwide utilizing the above-described materials, the market and applications for these types of products could be further extended if two major drawbacks to the use of these organic and wood by-product materials could be overcome, namely the lack of fire retardance and undesired swelling due to moisture. Until the present invention, the ability to enhance the flame retardance and fire resistance of materials such as OSB has been restricted to applying coatings to the surfaces of the finished OSB panels with minimal success. All previous attempts to treat such materials as OSB wafers or panels with conventional fire retardant chemicals (such as fire retardant treated plywood) with the use of phosphates, aluminates and other acid salts through pre-treating or pressure impregnation have been considered unsuccessful. Further, the OSB panels treated with such materials either lost an unacceptable amount of strength as measured by the modulus of rupture or lost dimensional stability as evidenced by swelling.
In addition, the construction and industrial products described above generally have poor termite resistance.
Accordingly, it is an objective of the present invention to overcome the above-described drawbacks by making organic and wood by-product construction materials, such as panels, with significantly reduced combustibility and swelling, e.g. those which are not readily combustible and which resist swelling upon being exposed to moisture, such as humidity.
Also, an objective of the present invention is to make organic and wood by-product construction materials which have excellent termite resistance.
Another objective of the present invention is to provide processes which impart these advantageous properties as well as others to organic and wood by-product materials.
Still another object of the present invention is to develop a composition which can be used to impart the above-described advantageous properties to organic and wood by-product materials.
Additional objects and advantages of the present invention will be set forth in part in the description which follows and in part will be readily apparent from the description or may be learned by practice of the present invention. The objects and advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.